Medical lasers have been used in various practice areas, such as, for example, urology, neurology, otorhinolaryngology, general anesthetic ophthalmology, dentistry, gastroenterology, cardiology, gynecology, and thoracic and orthopedic procedures. Generally, these procedures require precisely controlled delivery of energy as part of the treatment protocol.
Surgical laser systems utilize a frequency doubled Nd:YAG laser, which operates at 532 nm in a quasi continuous mode at high power levels (e.g., 106 watts) and has been used to efficiently ablate tissue. The frequency doubled Nd:YAG laser can be pumped by CW krypton arc lamps and can produce a constant train of laser light pulses. When ablative power densities are used, a superficial layer of denatured tissue is left behind. At high powers, 532 nm lasers induce a superficial char layer that strongly absorbs the laser light and improves ablation efficiency.
Many surgical laser procedures utilize a surgical probe, which generally comprises an optical fiber and a fiber cap over a distal end of the optical fiber to form a probe tip. A laser source delivers laser energy through the optical fiber to the probe tip where the energy is discharged through the fiber cap and onto desired portions of the targeted tissue.
Laser probe tips are typically assembled by attaching the fiber cap to the distal end of the optical fiber by fusing the glass fiber cap to the inner bare optical fiber after removing the polymer clad. Typically, a CO2 laser is used for this fusion process where the laser beam is focused on a portion of the fiber cap until the portion melts into the outer surface of the bare optical fiber. A thin walled fiber cap is used to assist in facilitating the welding process. This assembly process often leads to low yield due to the difficult fusing process, high costs due to the necessity of a laser station for the welding process, and product reliability concerns due to the thin walled fiber cap that is susceptible to thermal stress.